The only thing to bear in mind that whereas it is usual for an inside or outside cabin to have upeer and lower berths ie bunks. Balcony cabins usually have the two lower beds (made up as a double if needed) and the other is a double sofa bed. Hence space can become cramped although they will make sofa bed up in evening and fold back in day. Balcony cabins do not ususlaly have the upper berths.